Thank you so much for taking the time to respond, and for the outstanding information and advice.
Although increased moisture in the ears can predispose a dog to ear infections, the likely primary cause is seasonal allergies, which are also a common cause of seasonal hotspots, itching and skin infections. A hotspot is a localized bacterial skin infection, secondary to allergies/self trauma. The bacteria that are associated with hotspots are normal bacteria on the skin in low numbers, that overgrow and create the infection (just like the yeast in the ears are normal flora in low numbers, but overgrow due to allergic inflammation and moisture). If the flare ups occur only occasionally, then treatment of symptoms with occasional ear medications is fine, however if symptoms worsen and occur more frequently, then intradermal allergy testing and desensitization injections may be warrented. For now, regular (1-2 times weekly) cleaning of the ears with a mild astringent ear cleaner such as EpiOtic is recommended. For the hotspot, clipping and cleaning is sometimes all that is needed for mild hotspots, and you can also apply Otomax to the skin to reduce inflammation and superficial infection, but if it does not continue to improve then I recommend taking her to your veterinarian for possible antibiotics.
Kimberly Coyner, DVM
Diplomate American College of Veterinary Dermatology
www.dermvet.com
Edit to add:
Her ear infections are yeast infections, not mites.
I'm only going to post a comment because our Dermatologist (Dr. Coyner) will be on to discuss more completely.
Both bacterial and yeast (fungus) can cause ear infections. The bacteria could be the same as Staph is everywhere and a common contaminant of skin inflammation secondary to another cause.
Hot Spots are called Pyo-Traumatic Dermatitis. Meaning pus-producing infection with trauma a key component to the spot (typically the dog scratching at the highly itchy spots) this creates a viscous cycle of trauma, skin inflammation, oozing of serum, invasion or further growth of the bacteria and the cycle continues. They are seen often is hot humid climates (although can occur anywhere) and can flare up and spread very rapidly.
Your treatment was right on track; stop the inflammation, kill the bacteria, dry the skin and they usually calm down. Once a dog has these, they likely development them again.
I'm going to venture a guess and say that the ear infections are not related to where or why you saw the hot spot on her cheek. But...it's possible. Physical spread of the bacteria is a component of the infection.